In a wireless communications system designed to deliver data to a wireless mobile communication device (“mobile device”) such as a cellular telephone, a two-way pager, a wireless communication capable personal digital assistant (“PDA”), and other similar devices, there exist methods for formatting messages to enable data delivery. Data messages will frequently include a type of wrapper, or header, which is used to package a data payload. These headers traditionally include, among other information, the address of the intended recipient of the data message. The inclusion of the recipient device's address in the message header is typically used by a recipient to properly assess whether it is the intended recipient of the message. Including the recipient's address has two limitations: The inclusion of the recipient's address can add unnecessary bulk to a message and the inclusion of the recipient's address as the factor for determining to whom the message is addressed opens itself up to message spoofing attacks.
To avoid these limitations, it would be desirable to omit the inclusion of the recipient's address. However, conventional wireless systems present challenges if the recipient's address is removed.
For example, in a first type of conventional network, a Mobitex network for example, messages are broadcast and a mobile communications device must be able to accurately assess whether it is the intended recipient of the message. In this type of network, the traditional method used to address the problem of a mobile communications device assessing whether it is the intended recipient of a message is to add the recipient mobile communications device's address to the message so that a receiving mobile communications device can check the message to see if it includes its own address and is therefore destined for it. If the recipient mobile communications device's address is removed from a message this method can no longer function as required.
In a second type of conventional network, a General Packet Relay Service (GPRS) network for example, messages are readdressed to a mobile communications device, by a network node, using an internet protocol (IP) address which has been assigned to the mobile communications device by the network node and is separate and distinct from the mobile communications device's address. One feature of this type of network is that IP addresses are frequently reassigned to different mobile communications devices, when, for example, a mobile communications device is turned off or switches networks. In order to ensure that a message has been received by the correct mobile communications device, a mobile communications device cannot rely on examining the IP address but needs a mechanism which can be used to accurately assess an incoming message. If the recipient mobile communications device's address is removed from a message this method can no longer function as required.